1. Consider the following unbalanced equation:
HCl + MnO
2

H
2
O + MnCl
2
+ Cl
2
You have 5.00 grams of manganese(IV) oxide: a. How many moles of manganese(IV) oxide do you have? b. How many moles of HCl do you need for a complete reaction? c. How many grams of HCl do you need for a complete reaction? d. How many grams of each product (H
2
O, MnCl
2
, and Cl
2
) would be formed? e. Prove that mass has been conserved in this reaction. f. Is the number of atoms conserved? Support your answer. g. Is the number of molecules conserved? Support your answer.

2. Consider the unbalanced equation:
_____ C
6
H
14
+ _____ O
2

_____ CO
2
+ _____ H
2
O
Balance the equation
What mass of O
2
is required to react with 11.5 g of C
6
H
14
?
3. Consider the unbalanced equation:
_____ Na( s ) + _____ Cl
2
( g )

_____ NaCl( s )
What mass of NaCl can be produced from 25.0 g of Cl
2
and excess Na?
4. The mass of oxygen needed to completely react with 10.0 g of hydrogen to form water is reacted completely with methane to form carbon dioxide and water.
Write out and balance a reaction.
Determine the mass of carbon dioxide produced.
1. a. 0.0575 mol MnO
2
; b. 0.230 mol HCl; c. 8.39 g HCl; d. 2.07 g H
2
O, 7.24 g MnCl
2
,
4.08 g Cl
2
; e. 13.39 g = 13.39 g (8.39 + 5.00 = 2.07 + 7.24 + 4.08); f. yes; g. no a. 500 g MnO
2

1 mol MnO
86 .
94 MnO
2
2 = 0.0575 mol MnO b. 0.0575 mol MnO
2

4 mol HCl
1 mol MnO
2
2
= 0.230 mol HCl

c. 0.230 mol HCl

36.458g
HCl
1 mol HCl
= 8.39 g HCl d. 0.0575 mol MnO
2

2 mol
1 mol
H
2
MnO
O
2

18.016g
H
1 mol H
2
2
O
O
= 2.07 g H
2
O
0.0575 mol MnO
2

1 mol MnCl
2
1 mol MnO
2

125.846g
MnCl
1 mol MnCl
2
2 = 7.24 g MnCl
2
0.0575 mol MnO
2

1 mol Cl
2
1 mol MnO
2

70.90g
Cl
2
1 mol Cl
2
2. 81.1 g O
2
is required to react with 11.5 g of C
6
H
14
.
2C
6
H
14
+ 19O
2

12CO
2
+ 14H
2
O
= 4.08 g Cl
2
11.5 g C
6
H
14

1 mol C
6
H
14
86.172g
C
6
H
14

19 mol O
2
2 mol C
6
H
14

32.00g
O
1 mol O
2
2
3. 41.2 g NaCl can be produced from 25.0 g of Cl
2
and excess Na.
2Na + Cl
2

2NaCl
= 81.1 g O
2
25.0 g Cl
2

1 mol Cl
2
70 .
90 g Cl
2

2 mol NaCl
1 mol Cl
2

58 .
44 g NaCl
1 mol NaCl
= 41.2 g NaCl
4. 54.6 g carbon dioxide is produced. The students will have to determine and balance the equations, as well as think about how to set up the problem.
2H
2
+ O
2

2H
2
O
10.0 g H
2

1 mol H
2
2 .
016 g H
2

1 mol O
2
2 mol H
2
= 2.48 mol O
CH
4
+ 2O
2

CO
2
+ 2H
2
O
2
2.48 mol O
2

1 mol CO
2
2 mol O
2

44.01g
CO
2
1 mol CO
2
= 54.6 g CO
2